Direct injection gasoline engines have started to come back into widespread use since 2005 in Europe, and many gasoline direct injection rails in recent years are made of stainless materials that have excellent corrosion resistance. However, gasoline direct injection rails made of stainless materials may result in stress corrosion cracking when placed in a chlorine atmosphere or when a corrosive medium such as chlorine is contained in fuel.
On the other hand, steel materials are available in a wide variety of strengths and are inexpensive, and therefore steel materials attract attention as materials having better mechanical properties and greater cost advantages than stainless materials for higher-pressure systems of the future. Thus, recently, there are increasing demands for gasoline direct injection rails made of steel materials.
Patent Literature 1: JP 2012-97690A